MFI 10 Melt Flow Indexer User Manual

Part No. 01/2713
June 2012
MFI 10
Melt Flow Indexer
User Manual
MFI 10 User Manual
1
WARRANTY
This instrument is warranted against defects in workmanship, material and design for one (1) year
from date of delivery to the extent that AMETEK will, at its sole option, repair or replace the instrument
or any part thereof which is defective, provided, however, that this warranty shall not apply to instruments subjected to tampering or, abuse, or exposed to highly corrosive conditions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES WHETHER EXPRESS OR IMPLIED
AND AMETEK HEREBY DISCLAIMS ALL OTHER WARRANTIES, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY.
AMETEK SHALL NOT BE LIABLE FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES,
INCLUDING, BUT NOT LIMITED TO, ANY ANTICIPATED OR LOST PROFITS.
This warranty is voidable if the purchaser fails to follow any and all instructions, warnings or cautions
in the instrument’s Instruction Manual.
If a manufacturing defect is found, AMETEK will replace or repair the instrument or replace any defective part thereof without charge; however, AMETEK’s obligation hereunder does not include the cost
of transportation, which must be borne by the customer. AMETEK assumes no responsibility for damage in transit, and any claims for such damage should be presented to the carrier by the purchaser.
TRADEMARKS
AMETEK is a registered trademarks of AMETEK, Inc.
LLOYD INSTRUMENTS is a trademark of AMETEK, Inc.
DAVENPORT is a trademark of AMETEK, Inc.
Other trademarks are the property of their respective owners.
SUPPORT
AMETEK Lloyd Instruments Ltd
Steyning Way
Bognor Regis
West Sussex
UK
PO22 9ST
Tel:
+44 (0) 1243 833 370
Fax:
+44 (0) 1243 833 401
Email:techsupport@ametek.co.uk
Internet:www.lloyd-instruments.co.uk
AMETEK Measurement and Calibration Technologies
8600 Somerset Drive
Largo, FL 33773
USA
Tel:+1-727-536-7831
Tel:
+1-800-527-9999 (within USA only)
Email: chatillon.fl-lar@ametek.com
2
MFI 10 User Manual
Icons
WARNING
The raised hand icon warns of a situation or condition that may lead to personal injury
or death. Do not proceed until the warning is read and thoroughly understood. Warning messages are shown in bold type.
DANGEROUS VOLTAGE
The lightning icon warns of the presence of an uninsulated dangerous voltage within
the product enclosure that might be of sufficient magnitude to cause serious shocks
or death. Never open the enclosures unless you are an authorized and qualified
LLOYD INSTRUMENTS’ service personnel. Never open any enclosure when power
is connected to the system or its components.
CAUTION
The exclamation point icon indicates a situation or condition that may lead to equipment malfunction or damage. Do not proceed until the caution message is read and
thoroughly understood. Caution messages are shown in bold type.
NOTE
The note icon indicates additional or supplementary information about the action,
activity or concept. Notes are shown in bold type.
CAUTION
HIGH TEMPERATURES AND MOLTEN PLASTIC ARE
INVOLVED IN THE MFI PROCESSES.
ALL SPECIFIED SAFETY PROCEDURES SHOULD BE
STRICTLY ADHERED TO.
READ THIS MANUAL BEFORE USING THE MFI MODEL
10.
THE THERMOMETER(S) SUPPLIED ARE GLASS AND
CONTAIN MERCURY, PLEASE STUDY SECTION 8 OF
THIS MANUAL.
BEFORE USING THE MATERIALS TESTING MACHINE.
General Safety
General safety precautions must be followed
when using this LLOYD INSTRUMENTS product. Failure to observe precautions and warnings may result in damage to the equipment, or
injury to personnel.
It is understood that safety rules within companies vary. If a conflict exists between the material contained in all LLOYD INSTRUMENTS’
User’s Guides and the rules of a company using
a LLOYD INSTRUMENTS product, the more
stringent rules should take precedence.
Safety Considerations
The MFI 10 is completely enclosed and provides
no potentially hazardous outputs. Safety considerations are related to the power connections
and physical mountings.
Electronic and mechanical components housed
within the MFI 10 covers are to be serviced by
authorized LLOYD INSTRUMENTS’ representatives only.
MFI 10 User Manual
3
TABLE OF CONTENTS
1.0 1.1
1.2
1.3
1.4
INTRODUCTION................................
Melt Flow Rate....................................
Other Applications of the Apparatus....
Die Swell.............................................
Draw Down.........................................
5
5
5
6
6
2.0 MFI 10 ................................................ 6
2.1 Barrel (or Cyclinder)............................ 6
2.2Heater................................................. 6
2.3 Temperature Controller....................... 7
2.4 Indicating Thermometers.................... 7
2.5Dies..................................................... 7
2.6 Die Plate............................................. 7
2.7Piston.................................................. 7
2.8 Control Panel...................................... 8
2.9 Automatic Flow Rate Timer................. 9
2.10 Using the Control Panel...................... 9
2.11 Test Procedures.................................. 9
2.12 Test Setup.......................................... 17
2.13 Remote Control.................................. 21
2.14 Supervisor Mode................................ 22
2.15 Calibration Mode................................ 24
2.16 Startup Options.................................. 25
2.17 Ancillary Equipment........................... 25
2.18 Additional Features............................ 27
2.19 Additional Requirements.................... 27
3.0 3.1 3.2 3.3 INSTALLATION.................................
Unpacking..........................................
Temperature Control..........................
Cut-Off Timer Operation.....................
28
28
30
30
4.0 CALCULATION AND PRESENTATION
OF RESULTS.................................... 32
5.0 OPERATING TECHNIQUES.............
5.1 Cutting Off the Extrudite.....................
5.2 The Importance of Piston Grooves....
5.3 Form of Test Sample..........................
5.4Cleaning.............................................
5.5 Differences in Test Condition.............
33
33
33
33
33
35
6.0 AUTOMATIC FLOW RATE TIMER
OPERATION...................................... 36
6.1 Notes for Auto Flow Operation........... 36
6.2 Melt Density Calculations................... 36
7.0 GENERAL MAINTENANCE.............. 36
4
MFI 10 User Manual
8.0 THERMOMETERS............................ 37
8.1 Repairing Breaks in Mercury Column
Thermometers.................................... 37
8.2 Thermometers with Contraction and
Expansion Chambers......................... 37
8.3 Red Spirit Thermometers................... 37
8.4 General Care of Thermometers......... 38
9.0 TECHNICAL SPECIFICATIONS....... 39
10.0 CONNECTION LEADS...................... 40
1.0 INTRODUCTION TO MELT
FLOW INDEXING
1.1 MELT FLOW RATE
The melt flow rate (MFR) of a thermoplastic
material is the measured gravimetric flow of
the sample extruded through a die following
specified conditions of die length, diameter, temperature and pressure. Different standardised
conditions of extrusion temperatures and pressures are used for different types of polymer but,
for the purpose of comparison, samples of the
same type of polymer should be tested under
identical conditions.
The MFI Apparatus may be regarded as a
rheometer operating at conditions of low shear.
Although the shear stresses applied and the
resultant shear rates are much lower than those
used in the processes, the results obtained do
provide a useful indication as to the relative
ease with which different materials will flow
when processed. Since higher MFR values
indicate easier melt flow, a grade of polymer
with a high MFR is generally chosen when the
process envisaged involves relatively high rates
of shear, i.e. injection moulding. MFR is also a
measure of the molecular weight of a sample
and is indicative of the mechanical strength of
a material. Average molecular weight and MFR
are indirectly proportional, so that, although a
sample of high MFR will process more readily, its
melt strength is likely to be low.
1.2 OTHER APPLICATIONS OF THE
APPARATUS
In addition to determining the MFR, the apparatus can be used to measure other properties
of the polymer providing useful knowledge of its
behavior. By performing the MFR test under two
or more different loads, useful information about
the rheological properties of the material can be
found. It could be wrongly assumed that two
polymer samples with the same MFR will behave
in the same way with respect to output (shear
rate) when tested under the same conditions.
When subjected to the higher pressures (shear
stress) required for a moulding or extrusion
process, they could perform quite differently. If
the samples have different Molecular Weight
Distributions (MWD) the increase in the shear
rate resulting from an identical increase in shear
stress will be different as well. In general, a
MFI 10 Melt Flow Indexing Machine
large MWD corresponds with a greater shear
sensitivity, i.e. a higher rate of change in shear
rate per unit increase in shear stress. A useful
measure of the shear stress/shear rate relationship (flow parameter) can be made by measuring the samples MFR at standard load and at a
higher load. Increasing the test load (for polyethylene’s) from the standard 2.16kg to 21.6kg
loads, increases the level of shear rate by factor
between 50 and 100:1, depending on the MWD
of the sample and the simple arithmetic ratio.
MFR 21.6kg/MFR 2.16kg gives a measure of the
flow parameters.
Depending on the MFRs at 2.16kg load, the
value at 21.6kg can be equivalent to shear rates
more than 100 secs-1 coming, possibly, into
the range of extrusion processes. The facility
also exists to measure flow parameters at different temperatures giving an insight as to the
temperature sensitivity of the sample.
The extrudate generated during the test can also
be used to determine other useful parameters of
the sample. The emerging sample temperature
and the die diameter are known and its rate of
cooling and ambient temperature gives “controlled” conditions and is therefore repeatable.
Two important properties can be measured more
conveniently and with greater precision from
the Melt Flow Indexer than from commercial
processing equipment. These are Die Swell and
Draw Down.
MFI 10 User Manual
5
1.3 DIE SWELL
Die Swell or swelling ratio, is an arithmetic ratio between the diameter of the cooled extrudate at
ambient temperature and the diameter of the die. This is an important factor for processes such as
pipe extrusion and blow moulding.
1.4 DRAW DOWN
Draw Down is the extending of the polymer extrudate by its own weight as the extrudate lengthens. It
is, for example, a requirement of a polymer to have good draw characteristics in the blown moulding
process so that a good parison is produced.
Because the Die Swell and Draw Down depend on an accurate measurement of the extrudate, it is
important that the cross section should be as circular as possible. The most common cause of
irregular cross section circularity is draught, causing asymmetric cooling, the equipment should be
placed as far away as possible from any draught source.
DesiredMolecular
ProcessCharacteristic
Design
Blow Moulding
High Melt Strength
Low MFR
Film Blowing
Broad molecular weight distribution
Thermoforming
Extrusion
Low Die Swell
Narrow molecular weight distribution
Injection Moulding
Easy Flow
Medium to High MFR
Moderate Temperatures
Narrow molecular weight distribution
Rapid Cycles
2.0 THE MFI 10
The Melt Flow Rate apparatus has been designed in accordance with ISO 1133 and ASTM D1238
(Method B requires the Displacement Transducer, AFRT). ISO 1133 now supersedes all European
Standards such as DIN 53735 (Germany), NF: 51-106 (France), UNI 5640-74 (Italy) UNE 53098
(Spain). The apparatus is a dead weight extrusion plastometer with a microprocessor controlled melt
chamber (the barrel) in which, under standard set conditions, the test sample of polymer is heated
and extruded through a die with a known load. All component parts to perform the tests are calibrated
within stringent limits required by the above standards.
There are two tests; the manual cut-off (Procedure A) is suitable for materials with an MFR between
0.1 and 25g/10mins or for comparison of filled and unfilled polymers. The automatic method
(Procedure B) requires that the melt density either be known or calculated using the “calculate”
option in the embedded software. The AFRT automatically allows the flow rate to be measured and
is suitable for flow rates between 0.5 and 900g/10mins. (according to ASTM but only 100g/10mins
according to ISO 1133).
2.1 THE BARREL (OR CYLINDER)
The barrel is a steel cylinder, 50.8mm diameter and 162mm long, through which a smooth, straight
hole 9.55mm diameter has been bored and honed. The barrel is encased in a double layer of insulating material and the whole is housed in a sheet metal case.
2.2 THE HEATER
The barrel is heated by three cartridge heaters equally spaced around the central bore. Great care is
taken to ensure that all our barrel assemblies are produced to close tolerances to give the best heat
distribution and temperature stability.
6
MFI 10 User Manual
2.3 TEMPERATURE CONTROLLER
The temperature of the barrel is controlled by means of a platinum resistance thermometer (PT100)
in conjunction with a micro processor based, three term temperature controller. This enables the
operator to select any temperature within a standard range of 40-400°C which will be accurately held
to +0.1°C. The selection and adjustment of the barrel temperature forms part of the test set-up which
is entered from the console and saved when the machine is switched off.
2.4 INDICATING THERMOMETER
Indicating thermometers used for testing to standardised conditions are calibrated over a range of
4°C in steps of 0.1° C, For example, an indicating thermometer for use at the standard test
temperature of 190° C is graduated from 188° C to 192° C.
A standard range of these thermometers is available covering all the standard test temperatures laid
down in ISO 1133 and ASTM D1238. Long range thermometers can also be supplied covering the
working, range of 100° C to 300°C in three equal, 70° x 1.0°, overlapping ranges, 100 - 170°C,
165 - 235°C and 230 - 300°C.
2.5 THE DIE
Made of tungsten carbide, these conform precisely to standard dimensions; 8mm long, 9.47mm
overall diameter, bore diameter 2.095mm. The bore is very highly finished and is tested to tolerances
well inside the closest called for in any published standard, particularly with regard to bell-mouthing.
The alternative standard die called for in BS 2782 method 105C (as jet B) with a bore diameter of
1.181mm, is also available on request as an extra. Please note that this is no longer called for in the
Method 720A which replaces 105C, or in ISO 1133 which replaces the BS Standard, or the ASTM
Standard. However it is still in use for polymers with exceptionally high flow rates.
2.6 THE DIE PLATE
The die plate supports the die and is held in place underneath the barrel by three socket head
screws. The die plate is a piece of circular steel with three keyhole slots and a larger round hole in
the middle into which the ceramic insert is placed. The non-stick PTFE coating assist with cleaning,
and a ceramic insert withstands high temperatures and provide a rigid flat surface for the die to sit on. The ceramic insert sits slightly proud of the die plate in contact with the die and bottom of the barrel.
This concave underside enables the cut-off knife to cut the extrudate right up to the base of the die.
Insert screws to about half their length so that the die plate may be pushed up to the bottom of the
barrel and turned 10° to the engaged position. Do not over tighten the screws; it should be possible
to engage and remove the die plate without adjusting the screws and still have a tight fit between the
ceramic insert and the bottom of the die.
2.7 THE PISTON
There are two pistons, the standard version for use with weights up to 10 kg and one with guide bush
fitted for weights of 10kg and above. The guide bush is a metal tapered collar which slides up and
down the shank of the piston and provides extra rigidity with higher loads to prevent vectored loads.
The standard piston weighs 100g.
The solid steel piston has a head with a diameter of 9.47mm and a length of 6.35mm. The shank has
a diameter of 8.89mm and terminates with a portion of further reduced diameter which is covered by
an insulating, heat resistant sleeve. This forms a spigot upon which the loading weights are placed.
The purpose of this sleeve is to reduce (as far as practicable) the heat-sink effect of the weights. The
loose weights are tared to give the correct total load with the correct piston. Weights purchased with
model 6, 7, 8 or later, or since Lloyd Instruments acquired DAVENPORT are tared for use with the
heavier pistons.
MFI 10 User Manual
7
The shank of the piston is marked with two circumferential grooves so that the upper will be exactly
coincident with the top of the cylinder when the face of the piston head is precisely 20mm from the top
of the die, whilst the distance between the two grooves themselves is 30mm. The purpose of these
grooves is explained later in this manual.
Please note; that in the early stages of the development of the Melt Index method of characterising
polymers, HOLLOW pistons weighing only 58g were extensively used.
They were later abandoned as the need for heavier test loads became apparent, since they lacked
the necessary mechanical strength. Weights which have been tared for use with the hollow pistons
WILL NOT BE CORRECT for use with the later solid pistons. This fact should be considered if you
decide to use weights other than those supplied with the apparatus.
2.8 CONTROL PANEL
MFI 10 Control Panel Layout
This is used to display information and to enter test set-ups. The set temperature and actual temperatures are both displayed at all times. The lower group of green numbers shows the set
temperature, while the upper group of red numbers shows the actual barrel temperature. LED’s provide quick status indication. The band of five LED’s to the right of the temperature displays indicate
the temperature relative to the set temperature.
The centre green LED will be lit when the actual temperature is within ±0.1°C of the set
temperature. The amber LED’s indicate that the temperature is between 0.1°C and 0.5°C
from the set temperature and the outer red LED’s will be lit when the temperature is more
than 0.5°C from the set temperature.
The alphanumeric LCD provides user instructions and allows easy entry of the test parameters. An audible beeper helps to prompt the operator and provides end of preheat and
sample cut-off warning signals.
8
MFI 10 User Manual
The numeric keypad is used for entering parameters. The blank key grouped with the numeric keys
is used to select calibration mode. The four keys directly under the LCD display a soft keys used to
select from the list of options displayed on the second line of the LCD.
More detailed information on setting up tests and displayed messages is given in The MFI 10, Test
Set-up section of this manual.
2.9 AUTOMATIC FLOW RATE TIMER (Optional Equipment)
This attaches to the side of the MFI and the lead plugs into the 9 way socket on the right hand side of
the column. The Automatic flow rate timer derives its power from the MFI. All readings are
automatically handled by the MFI. The distance over which a test is performed is programmed as
part of the test set-up described in the relevant section of this manual. Standard distances are 2mm
and 20mm ISO 1133 and 6.25mm (1/4 inch) and 25.4mm (1 inch) for ASTM D1238.
2.10 USING THE CONTROL PANEL
The top line of the LCD provides the user with information or instructions. The second line displays
messages which are used to define the function of four soft keys located directly under the LCD
display. Where messages are displayed on the second row, simply press corresponding key to select
the required option.
2.11 TEST PROCEDURE
Davenport Melt Flow Indexer
V 1.0 30/1/09
This sign on message is displayed for 3 seconds following power ON. After this time the display will
automatically clear and the next message will be displayed. The second line shows the version number of the embedded software and its release date. If the internal EPROM is replaced with a different
version number, the new version will be displayed. A change of version will cause the internal working memory to be re-initialised. This will result in the loss of all test set-ups which have previously
been saved. Temperature calibration information will not be lost.
Select Test Standard
SelectEdit f
g
This screen is displayed when the user needs to select one of the pre-programmed test set-ups or
to define a completely new one. It is also displayed when a test is aborted at any point, allowing the
user to select a different test type. The default test set-up is the one which was current when the
machine was last switched OFF. The f and g options scroll through the available test set-ups. The
Edit button will allow the user to customise the test set-up. This display will not normally be shown
after power ON.
To force this screen to be shown at power ON the appropriate option in the test set-up for the default
test must be set. See the section on setting up the test for more information.
MFI 10 User Manual
9
Pressing select will advance to the next screen and tell the temperature controller to start heating the
barrel to the temperature specified in the selected test set-up.
No AFRT fitted please connect
IgnoreAbort
This screen is only displayed when the test requires an AFRT and none is connected. Connect an
AFRT or select Ignore to perform test using cut-off method.
No weight loading fitted please connect
IgnoreAbort
This screen is only displayed when the test requires the weight loader and none is connected.
Connect a weight loader or select Ignore to perform test using manual weight loading method.
Push AFRT to its lowest position
Abort
If the test uses an AFRT, the MFI needs to know the current AFRT position relative to the barrel. By
pushing the AFRT to the bottom of its stroke, a micro switch is activated which provides a reference
position for the MFI. This information is only needed if the MFI has been switched OFF. If the AFRT
has been disconnected or if the internal working memory has been initialized, it will be necessary to
re-calibrate the AFRT. This is a simple procedure which will automatically be invoked when required.
Follow the on screen instructions or see the section on AFRT calibration for more details (page 36).
Moving Weight Loader, please Wait
StopStopStopStop
This screen is displayed whenever the weight loader arm is moving. If the test uses the auto weight
loader then is must be positioned in its upper position before the test can start. If it is not in the upper
position, it will be moved there automatically with the above message displayed.
Pressing any option key will stop the weight loader before it reaches the top.
NOTE: The Automatic Weight Loader is optional equipment and is not supplied as standard
with the MFI10.
10
MFI 10 User Manual
Heating Barrel, please Wait
Loader Abort
This screen is displayed while the temperature controller is setting the barrel to the required temperature. When the barrel temperature is stable within ±0.1°C for a minimum of 10 seconds, the buzzer
is sounded and the next message is displayed. If an auto weight loader is connected to the MFI 10 it
can be manoeuvred manually by selecting the Loader key.
Move Weight Loader?
81mm 71mmBottomFinish
Move Weight Loader?
Top Bottom71mm Finish
When the auto weight loader is to be driven manually, one of the above screens will be displayed.
The exact options will depend on the actual position of the weight loader arm. Press Finished to end
manual operation of the weight loader. If the weight loader is in the wrong position it will automatically
reposition itself before continuing the test.
Weight Loader Door Open, please Close
Abort
The weight loader arm can only be moved if both doors are closed. If either door is open the above
message is displayed.
Load Sample
CompressLoader
Abort
This screen instructs the operator to start charging the barrel with the sample to be tested. The same
sample mass of the test polymer should be loaded every time to improve repeatability of the test,
especially in QC situations, Please refer to fig 72. As soon as the charging process has been started
the Compress button should be pressed. This starts the preheat timer and displays the next message. Note that the time spent compressing the sample is included in the preheat time.
NOTE: While pouring sample into funnel, agitate the funnel slightly from side to side. This
will speed loading.
MFI 10 User Manual
11
Compress Sample
OK
Abort
The sample should now be compressed. Press OK when you are satisfied that the sample has been
compressed and there are no more air bubbles (Air bubbles create a “popping” sound) This process
should be continued for a maximum of one minute. After this time the audible beeper will sound and
the next message will be displayed.
NOTE: Compress sample firmly. Do not move the compression tool up and down. This
will introduce bubbles and cover the side of the barrel with plastic, causing possible friction
between the piston and barrel.
Fit Piston on its Support
OK
Abort
Having compressed the sample, the piston should be fitted with its support. This message will
automatically clear after 10 seconds. Two piston supports are provided, one 81mm long for high
flow rate polymers (up to 5g/10 mins) and one shorter, 71mm, for low flow rate polymers under 5g/10
Fit Piston
OK
Abort
Fit Weight (2.16Kg)
OK
Abort
mins. When using the auto weight loader, the message reads:
The weight should now be fitted to the top of the piston. The figure in parenthesis is the weight entered as part of the test set-up and is included here to assist the user. This message will
automatically clear after 10 seconds. When using the auto weight loader, the weights will be lowered
automatically without showing this message. The auto weight loader will automatically stop when it
reaches the pre-set stop position corresponding to a spacer height of either 71mm or 81mm. If neither
Attach AFRT Sensor
OK
Abort
option was set during the test set-up the loader arm will continue to its bottom position.
If the selected test requires the use of the AFRT, it should now be attached to the bottom of the
weight. If the AFRT is not required, this message will not be displayed. This message will
automatically clear after 10 seconds.
12
MFI 10 User Manual
Pre-heating Sample 2:30 (6:00)
Release
Abort
The system will now continue preheating the sample for the time set in the test set-up. This would
normally be a total of 6 minutes from when the sample is first entered into the barrel. The preheat
time elapsed is displayed with the total preheat time shown in parenthesis. If using the auto weight
loader, then at the end of the preheat time the auto weight loader arm will be moved to the bottom
position. This will release the weights and allow the test to start automatically. By pressing the key
marked Release, the weight loader arm can be lowered before the end of the preheat period. The
Release option is not displayed if the auto weight loader is not in use.
Remove Piston Support
OK
Abort
If the auto weight loader is not being used, then at the end of the preheat period the piston support
should be removed allowing the piston to fall freely. This message will automatically clear after 10
seconds.
Pre-Heat finished, start test? 6:30
OK
Abort
If the manual cut-off method is being used the operator will now be waiting for the lower piston scribe
mark to enter the top of the barrel. As soon as this happens the Start key should be pressed and the
waste extrudate cut-off at the same time. The time displayed is the total test time commencing from
when the sample was first entered into the barrel. The next screen for the cut-off method is shown if
the test start time is not reached. If the AFRT is being used, the following message will be displayed
instead.
Pre-Heat finished, awaiting start 6:30
Abort
When the lower piston scribe mark enters the barrel, the MFI will automatically start to measure the
time taken for the AFRT to move through the specified distance.
MFI 10 User Manual
13
Test start time not reached. 6:30
Continue
Abort
The test set-up allows the user to enter a minimum time from when the sample is entered into to the
barrel to when the first measurements should be taken. This message will only be displayed if the
minimum time has not been reached. The user has the option to Continue or Abort the test. If
Continue is selected before the minimum time is reached, a warning message will be printed if the
results are sent to a printer. For most tests the minimum time will be 6 minutes, the same as the
preheat time, so this situation should not occur.
Cut Off Waste
Abort
This message is only displayed if the cut off method is being used. It is automatically cleared after 5
seconds.
Test Start time exceeded
Continue
Abort
The test set-up allows the user to enter a maximum time from when the sample is entered into to the
barrel to when the first measurements should be taken. This message will only be displayed if the
maximum time has been exceeded. The user has the option to Continue or Abort the test. If
Continue is selected, a warning message will be printed if the results are sent to a printer.
Cut-Off Time 25 sec (60 Sec)
Last
Abort
If the cut off method is being used, this message will be displayed showing the time remaining until
the next cut off should be made. The figure in parenthesis is the total cut off time for this test. During the last 2 seconds prior to the cut off 2 short audible beeps will sound followed by a longer
beep telling the user to perform the cut off. This sequence of beeps is designed to improve the
accuracy of the manual cut off method by reducing user induced error. The beeps may optionally be
turned off by using supervisor mode. When the time reaches zero and the cut off beep is sounded,
the display shows the following message, telling the user to cut the sample. When the last cut off
has been made the operator should press the Last key. All cut offs should be made before the upper
scribe mark on the piston enters the barrel. If the AFRT is also being used, the test will end automatically if the upper scribe mark on the piston enters the barrel.
NOTE: The Automatic Cut-Off device is optional equipment and is not supplied as standard
with the MFI10.
14
MFI 10 User Manual
Cut-Off Sample
Continue
Abort
This message is displayed for 5 seconds. It is then cleared automatically and the previous message
is displayed. The Standards both require at least 3 good cut-offs to be made. Cut-offs containing air
bubbles should be discarded and the good cut-offs weighed and recorded in the order in which they
were cut.
Performing AFRT Test
Abort
If the cut off method is not used, or if the cut off test is finished before the AFRT test, this message will
be displayed. This message will automatically be cleared when the AFRT test is finished or when the
upper piston scribe mark enters the barrel.
At the end of the test, if the auto weight loader was used, it will be automatically raised to the top
position ready to begin a new test.
Sample Weight (g) [ 1] 0.234
FinishedEnter
BkSp Abort
This screen, displayed if the cut off method was used, allows the user to enter the weight of each cut
off. The user can enter the weight to 5 decimal places followed by Enter. The Standards both require
the cut-offs to be weighed to 4 decimal places. If the user is re-entering the sample weights after
the results have been displayed, the Abort message is replaced by Delete. This allows the user to
remove any weights from the calculations.
Cut-off MFR (g/10 min) 1.0525
Re-Weight
More
Print
New Test
This display shows the melt mass-flow rate (MFR) of the sample tested using the Cut-Off method. If
the Cut-Off method was not used, this display is not shown. If the AFRT was also used, the More
option is provided for displaying additional results, otherwise this option is not shown.
MFI 10 User Manual
15
Repeat
AFRT MVR (cc/10 min) 1.4700
More
Print
New Test
This display shows the melt volume-flow rate (MVR) of the sample tested using the AFRT method.
The More option is provided for displaying additional results.
Melt Density (g/cc) 0.6410
More
Print
Repeat
New Test
This display shows the Melt Density of the sample tested using a combination of the MFR obtained
from the Cut-Off method and the MVR obtained from the AFRT method. If the test set-up does not
specify that the melt density is calculated, this display is not shown.
Repeat
AFRT MFR (g/10 min) 1.0525
More
Print
New Test
This display shows the melt mass-flow rate of the sample tested using the AFRT method. It is
calculated using the result for the MVR and the value entered for sample melt density as part of the
test set-up. If the AFRT was not used, or if the test set-up specified that the melt density should be
calculated, this display is not shown.
NOTE: Selecting Repeat from any of the above screens will repeat the test using the same
test set-up parameters. More will display the next results screen as applicable for the type
of test performed. Print will display the following screen and New Test will enable a different
test set-up to be selected, or edited.
Select printout options
Test SetupSamples
Results
All
This display allows the user to select what information is to be printed. Selecting All will print Test Set-
Printing ...
Abort
up, Samples and Results in one go.
This display is shown while printing is in progress. Pressing Abort will cancel printing.
16
MFI 10 User Manual
2.12 TEST SETUP
The following series of screens are used to set up the test method. Where Yes/No options are
offered, the existing setting is displayed above the left hand key. Where values are to be entered,
the previous value is offered as a default and can be selected by pressing Accept which is displayed
above the left hand key. As all existing defaults can be selected by pressing the left key, it is a simple
matter to edit one part of a test set-up without having to remember all of the other settings. After
setting all of the options, they can be saved into non-volatile memory. Up to ten test set-ups can be
saved and recalled later. Two Standard Test Set-ups are provided as examples. One uses manual
cut-off method, the other uses the AFRT. These can be used as they are or modified to suit individual
requirements.
Enter Password
AcceptChange BkSp
If a user password has been set-up in supervisor mode, then it is necessary to enter the password
before the test set-up can be modified. This provides a level of security which enables only
supervisors to modify the test set-up. If no password has been set-up, this display is not shown.
English Messages
OK
f
g
The language used can be selected and saved as part of the test set-up. This enables each test setup to use a different language.
Yes
AFRT Used?
No
Selects whether the AFRT is to be used for the test. The AFRT is required to calculate results in
accordance with ISO 1133 and ASTM D 1238 Procedure B.
AFRT Distance (mm) 2.00
AcceptChange BkSp
If an AFRT is to be used, it is necessary to set up the distance over which the AFRT is to be timed.
If a single measurement is to be taken, this can be anything up to the full test range of the AFRT,
usually 30mm. If multiple readings are to be taken, the total must be less than the AFRT range. The
value entered is the distance for each reading. This option is bypassed if the AFRT is not used.
Number of AFRT readings 5
AcceptChange BkSp
This specifies the number of readings that will be taken at the distance entered in the previous
section. ISO 1130 Procedure B specifies that at least three measurements should be taken. This option is bypassed if the AFRT is not used.
MFI 10 User Manual
17
Material Melt Density (g/cc) 0.760
AcceptChange BkSpCalculate
This allows the user to enter the melt density for the material to be tested if it is known. This value
is used to calculate the melt mass flow rate (MFR) from the melt volume flow rate (MVR) determined
from the AFRT test. The density shown is for the standard PE resin used to test all systems prior
to shipment! NB; The melt density is NOT the same as the (Solid) density and may be calculated:
r = m divided by 0.711 x i. Where r = density in g/cc of the melt at the test temperature and m = the
average mass in grams of the cut-offs and i = predetermined distance moved by piston. The user
may also select Calculate, in which case both AFRT and Cut-Off tests can be performed simultaneously. The melt density is calculated from the results obtained from each type of test. If Calculate is
selected, the following option to use Cut-Off method is automatically set to Yes. This option is not
offered if the AFRT is not used.
Yes
Cut-off method
No
Selects whether the Cut-Off method is to be used. If the AFRT is not used, this is automatically set to
Yes. It is also set to Yes if The AFRT is used and the option to calculate melt density is chosen. The
Cut-Off method is required to calculate results in accordance with ISO 1133 Procedure A and ASTM
D1238.
Yes
Use Auto Cut-off?
No
If the Cut-Off method is to be used and an auto cut-off device has at some time been connected to
the MFI the test can be configured to use the auto cut-off device. If Yes is selected, then during a
test, when a cut off is due to made, the auto cut-off device will be automatically triggered.
Allow MFR Spead (%) 15.0
AcceptChange BkSp
This sets the maximum MFR spread which is allowed from the Cut-Off test. If the total spread is
above the entered value, a warning message is printed with the test results. It is calculated as the
difference between the maximum and minimum sample weight divided by the average weight of the
samples. Any value in the range 0% to 100% can be entered although ISO 1133 Procedure A
specifies that a maximum spread of 15% is allowed. This option is not offered if the Cut-Off method
is not used.
18
MFI 10 User Manual
Cut-off time (Secs) 60
AcceptChange BkSp
The Standard specifies the Cut-Off time for each sample according to the flow rate. An audible
beeper is sounded each time the set time period expires. The timer will then be reset automatically.
Any value in the range 4 seconds to 999 seconds can be entered and will depend on the material
being tested and the weight applied. A Cut-Off time should be chosen which gives a Cut-Off length
of between 10mm and 20mm for the given sample. This option is not offered if the Cut-Off method is
not used.
MFI g/10mins
0.1 to 0.5
>0.5 to 1.0
>1.0 to 3.5
>3.5 to 10
>10
Extrudate cut-off time intervals (S)
2401
120
60
30
5 to 152
OTE: (1) ISO 1133 Recommends the measurement of MFIs between 0.1g /10mins and
N
100g/10mins, although ASTM D1238 allows measurements up to 50g/10mins.
OTE: (2) ISO 1133 recommends that all polymers with an MFR greater than 25g/10mins
N
use Procedure B or an automatic cut-off device accurate to less than 0.1 second. This is to
ensure adequate repeatability.
Set Temperature (°C) 190.0
AcceptChange BkSp
Determines the temperature at which the test is to be performed. Any value in the range 40°C to
400°C can be entered.
Weight used? (Kg) 2.160
AcceptChange BkSp
Allows the user to enter the value of weight which is to be used for the test. The value entered here
is used as a prompt when the operator is instructed to fit the weight, thus reducing the likelihood of
operator error if multiple weights are available. The weight is also quoted in the test report printed at
the end of the test.
MFI 10 User Manual
19
Preheat Time (Mins. Secs) 6.00
AcceptChange BkSp
Allows entry of any preheat time in the range of 1 minute to 99 minutes in 1 second steps. This is the
total time from when the sample is first charged into the barrel to when the first cut-offs can be taken,
including the time spent charging the sample. The ISO 1133 Standard recommends 6 - 8 mins.
Min Test Start Time (Mins. Secs) 6.00
AcceptChange BkSp
This is the minimum time that must elapse from when the sample is first charged into the barrel to
when the first cut-offs can be made or AFRT readings taken. If this minimum time is not reached,
a warning message will be displayed on the LCD. The user then has the option of aborting the test
or continuing. If to continued within the minimum time a warning message is printed with the test
results.
Max Test Start Time (Mins. Secs) 8.00
AcceptChange BkSp
This specifies the maximum time which may elapse between first charging the sample and taking the
first Cut-Off or AFRT reading. If this time is exceeded, the user has the option of aborting the test. If continued, a warning message is printed with the test results.
Max Total Test Time (Mins. Secs) 25.00
AcceptChange BkSp
This specifies the maximum total duration for the test. If this time is exceeded, a warning message is
printed with the test results.
Yes
Use Weight Loading System?
No
Asks whether the auto weight loader should be used for the test. The option is only offered if an auto
weight loader has at some time been connected to the machine.
Accept
Pause Weight Loading System? 81mm
71mm
81mm
No Pause
If the auto weight loader is to be used, it can be programmed to pause at a position equivalent to
using either a 71mm or a 81mm spacer to support the weights. If the pause option is not required,
this can also be selected.
20
MFI 10 User Manual
Start heating barrel when switched ON?
Yes
No
If this option is set to Yes (default setting), the barrel will automatically begin heating as soon as the
MFI is switched ON. If it is set to No, at switch ON a screen will display the prompt for the test set-up
procedure. The barrel will only be heated when a test set-up has been selected.
Start heating barrel when switched ON?
Accept
h
i
g
This screen allows the user to specify a name for the test set-up. Any name up to ten characters long
may be entered. The UP and DOWN arrows are used to change the letter indicated by the underline
cursor.
A list of alphanumeric characters and some special symbols is provided. Pressing the RIGHT arrow
will advance the cursor to the next letter. After the tenth letter, the cursor is returned to the start of the
name. The name entered is the one displayed when selecting the test set-up at the start of a test.
Pressing Accept advances to the next screen.
Setup Complete. Save Options
SaveCreate New
Abort
Having programmed all of the test set-up options, they can now be saved into non-volatile memory
to be called up later. Selecting Save will overwrite the previous version of this test set-up. Selecting
Create New will not overwrite the previous version but will create a copy of it with the changes just
made.
2.13 REMOTE CONTROL
The MFI 10 can be controlled from a computer using the Nexygen MFI software (p/n 40/0734).
Select
Select Test. Remote
Edit
f
g
This requires Version 1.6 or later of the embedded software. To do this the Remote test setup must
be selected. The Remote test setup can be edited by pressing the Edit button, however, only the
language option can be changed. The Remote test setup is selected by pressing the Select button.
This will display the next screen.
MFI 10 User Manual
21
Cannot connect to remote computer
Abort
Nexygen will start the connection process. If this is not completed the MFI 10 will remain in this
state for 10 minutes, after which it will automatically return to the Select Test option. During this time
the Abort button will also display the Select Test option. The Calibrate button will start the calibrate
mode, for more details of the calibrate mode see the Calibration Mode section of this manual (page
35). When the Nexygen has finished the connection process the next screen will be displayed
Under control of remote computer
automatically.
When this message is displayed the MFI 10 will be controlled by the Nexygen MFI software and will
not respond to any local button press.
2.14 SUPERVISOR MODE
This mode can be entered when the MFI is switched ON by pressing the first option key followed by
the third option key while the Davenport sign on message is displayed. This provides the following list
of system configuration options. Many of these options will never need to be changed.
Enter Password
AcceptChange BkSp
If a password has been set-up, then it is necessary to enter the password before the following
options can be modified. This provides a level of security which enables only supervisors to modify
the configuration. If no password has been set-up, this display is not shown.
AFRT start pos above die (mm) 50.0
AcceptChange BkSp
This screen allows the user to enter the position at which the AFRT test will begin. The figure
specifies the distance between the lower edge of the piston head and the top of the die. ISO 1133
specifies that this distance should be 50mm and that is the default setting in our factory. The ASTM
AFRT end pos above die (mm) 20.0
AcceptChange BkSp
Standard requires the piston to be 48mm above the die.
This screen allows the user to enter the position at which the AFRT test will end. The figure specifies
the distance between the lower edge of the piston head and the top of the die. ISO 1133 specifies
that this distance should be 20mm.
22
MFI 10 User Manual
Yes
Enable buzzer
No
The audible beeper can be switched off by selecting No. This may be useful where several MFI
machines are operating in close proximity or the test has been fully automated by addition of the
AFRT and the auto weight loading system. Default setting is that the buzzer is enabled.
Yes
Cut-off warning Bips?
No
This option allows the user to select whether the two short bips which are sounded before a Cut-Off is
to be made are to be enabled. Select No if you do not require these bips. Default is bips enabled.
Yes
Enable Calibration mode?
No
Calibration mode can be entered by pressing the calibration key, ( the blank key at the bottom left
hand corner of the numeric key pad), during any part of a test. (not during test set-up). This option
allows calibration mode to be disabled. Default setting is with calibration enabled.
Enter new password
AcceptChange BkSp
None
If a password already exists, it can be confirmed by pressing Accept. A new password can be entered
by pressing Change. If a password is no longer required, selecting None will remove the password.
The password may be up to eight characters long and made up using any of the numeric keys on the
keypad.
Test new password
AcceptChange BkSp
If the password has been changed the user will be prompted to re-enter the password. The password
should be typed in exactly as before followed by Enter. If the password has been re-entered correctly,
it will be accepted. If the two entries are different, the user will be prompted to enter the password
again.
MFI 10 User Manual
23
2.15 CALIBRATION MODE
Calibration mode can be entered by pressing the calibration key ( the blank key at the bottom left
corner of the numeric keypad) from any of the test states. It cannot be entered from the test set-up
state. Calibration mode allows calibration of the temperature controller and AFRT. Note that the
AFRT must be re-calibrated whenever the internal working memory is cleared. The barrel temperature should only be calibrated when the temperature control loop is active and the barrel temperature is stable. The temperature calibration data is not erased when the internal working memory is
erased.
Adjust until display reads OK
OK +0.1°C-0.1°CFollow
This display allows calibration of the temperature controller. The temperature can be calibrated at
any set temperature by placing a calibrated thermometer in the barrel of the MFI. For best results the
thermometer should be surrounded by a polymer having similar characteristics to the polymer to be
tested. If the system is calibrated again at the same set temperature, the previous calibration value
is overwritten. If the system is calibrated at a second set temperature, the calibration value stored at
the original set temperature is not affected. To calibrate the temperature at ambient, the set temperature should be adjusted to a value around ambient. Calibration may be performed at a maximum of
fifty set temperatures. Pressing +0.1°C or -0.1°C will increment or decrement the displayed actual
temperature by 0.1°C. This is only adjusting the displayed value, not the value currently used by the
temperature control loop. When the displayed temperature is correct, Follow can be pressed. This
will tell the temperature control loop to use the displayed temperature reading for controlling the barrel temperature. This Follow message will change to display Hold. Further pressing of the +0.1°C or
-0.1°C keys will change the displayed temperature and force the control loop to adjust the barrel
temperature accordingly. Pressing Hold will tell the temperature control loop to maintain the
temperature at the last set temperature regardless of further changes to the displayed temperature.
Press OK when the displayed temperature matches the temperature of the calibration thermometer.
To exit without changing the calibration data stored, press the calibration key again.
OTE: Load 2g of PE or the polymer you normally test into the barrel. Compress to expel
N
air bubbles. Insert the thermometer holder (a brass cylinder about 8cm long with two vertical
sections cut out on either side about 2cm long) Then insert the thermometer to its full length
so that the 90° angle piece rests on top of the barrel cover. The brass holder ensures that
the thermometer remains vertical and straight. The 90° angle on the thermometer ensures that
the thermometer measures at the precise distance above the die orifice. Correct the temperature
controller if necessary, after 4 minutes has elapsed and both the thermometer and barrel
temperature are stable.
Push AFRT to its lowest position
10.5432
The AFRT uses an optical encoder to measure distance moved. This cannot provide an absolute
position so the AFRT uses a micro switch as a reference mark. The micro switch is activated by
pushing the AFRT arm to its lowest position. Activation of the micro switch will zero the counter
associated with the optical encoder and will automatically be detected by the MFI software. The
number displayed in the lower right hand corner of the LCD indicates the AFRT arm position relative
to its position when attached to the weight with the piston resting on the die.
24
MFI 10 User Manual
Fit die, piston and weight. Attach AFRT
OK 10.5432
By assembling the components in a clean condition as instructed, the MFI control software can
measure the distance from the reference micro switch to this position.
Press OK to indicate that the system is correctly set-up. Once this has been done, the system control
software can determine test start and end positions by moving the AFRT arm down to the micro
switch.
2.16 STARTUP OPTIONS
It is possible to force certain actions when the machine is first switched ON by pressing certain keys
or sequences of keys while the Davenport sign on screen is displayed.
Internal Working Memory Initialization can be forced by pressing the right hand option key during the
Davenport sign on message. This forces all internal working variables to be cleared and will result in
the loss of all test set-ups and AFRT calibration. Temperature calibration will not be lost.
Hardware Test Mode can be forced by pressing the left hand option key twice while the sign on
message is displayed. This mode is used for testing the internal electronics of the MFI and should
only be used by qualified test personnel.
Supervisor Mode can be started by pressing the left hand option key followed by the third option key
from the left. See the section THE APPARATUS, Supervisor mode for details of options available in
the mode.
System Test Mode can be entered by pressing a sequence of three keys while the Davenport sign
on message is displayed. Counting from the left the first key, followed by the third key and then the
second key must be pressed in sequence. A special password is required to enter this mode. When
this mode has been selected, operation is as normal but no limit is placed on the values which can
be entered. This facility is used for testing the barrel over temperature trip which needs to be set at
450°C.
2.17 ANCILLARY EQUIPMENT
All equipment should be kept clean and stowed away after use. The long tools, including the piston,
each slot into the holes in the top cap. The small tools should be kept in the drawer in the base of the
MFI. The draw contains cut-outs sections for each tool so that the tools do not roll around and get
damaged. Missing items are easily identified.
2.17.1CHARGING TOOL
A non-metallic rod for tamping the test charge in the cylinder.
2.17.2 DIE EJECTOR
A steel rod with a special soft alloy tip to avoid any possibility of damaging the die. Used to push the
die up and out of the cylinder.
2.17.3CLEANING TOOL
For cleaning the bore of the cylinder.
MFI 10 User Manual
25
2.17.4CUT OFF KNIFE
Designed specially for cutting off the extrudate.
2.17.5CIRCULAR SPIRIT LEVEL
Fitted with a thermal insulating foot so that it can be placed on top of a hot barrel without suffering
damage. For levelling the apparatus.
2.17.6 DIE BROACH
For cleaning the bore of the die.
2.17.7 HEXAGON KEY
For loosening the die plate retaining screws.
2.17.8 TWO PISTON SUPPORT SLEEVES
For restricting the movement of the piston during the pre-heat period.
One of 71mm length for low flow rate polymers.
One of 81mm length for high flow rate polymers.
2.17.9 THERMOMETER SLEEVE
Brass cylinder with two vertical cut-outs
Designed to hold the calibration thermometer absolutely straight and make sure the mercury bulb is
directly above the die orifice.
2.17.10 DEAD WEIGHT
Weighing exactly 2.06kg, which together with the piston makes up the most common standard test
load of 2.16kg.
2.17.11CERAMIC INSERTS
NOTE: These should be changed if chipped or polymer has built up.
2.17.12FUNNEL
To help loading with the loading of polymer.
There is also a powder funnel available to special order with an extension into the barrel to avoid
polymer sticking to the side of the top of the barrel.
2.17.13 DIE PLATES
PTFE coated to prevent polymer sticking to the 3 key hole slots to ensure quick and simple removal
and replacement.
2.17.14CALIBRATION THERMOMETER
90° angle, indicating, mercury in glass, 4°C x 0.1°C
2.17.15 BOX OF CLEANING PATCHES
Used for cleaning the barrel.
26
MFI 10 User Manual
2.18 ADDITIONAL FEATURES
With the exception of the test loads, all items required to perform Melt Flow Index tests are housed
within the cabinet of the apparatus, thus being a totally stand-alone work station using the minimum
amount of bench space. To assist in both the cleaning of the barrel and manual operation, i.e. Cut-Off
principle, the automatic flow rate timer sensor unit is able to be swung away from the barrel housing
to a park position, thus giving easy access to the barrel entry and die plate. When required, the
automatic Flow Rate timer sensor unit is easily returned to its position near the barrel. The apparatus
has a built in over-temperature protection relay. If the temperature of the barrel exceeds the pre-set
Cut-Off point, the heaters will be disconnected.
2.19 ADDITIONAL REQUIREMENTS
Certain additional equipment is required for use of the apparatus but is not supplied as standard
equipment (commonly available in most laboratories). The principle item is an analytical
LABORATORY BALANCE capable weighing to 4 decimal places. If you are only using the automatic
Procedure B AND the melt density is known, this equipment will not be necessary.
All users will require a top pan balance capable of weighing to 2 decimal places for weighing out the
sample charging mass.
A Scotchbrite pad (flat rectangular pan scourer available from most supermarkets) is ideal for
polishing the die once the bulk of the polymer has been scraped off with the cut of knife.
MFI 10 User Manual
27
3.0INSTALLATION
3.1UNPACKING
All packing material should be carefully removed from the MFI machine and a careful visual
inspection should be made to ensure that there is no obvious transit damage. The following items
should be in this package:
Supplied items
Quantity
Part No
This User Manual
1
01/2713
Melt Flow Indexer model 10
1
(depending on order)
Die plate casting
1
737/8
Ceramic die plate insert
2
737/7
Standard die 2.096mm bore
1
338/10
Die broach standard diameter
1
338/101
Standard piston assembly
1
338/45
Weight 2.16kg 1
338/14
Cut-off Knife
1
338/33
Charging tool
1
338/52
Die ejection tool
1
338/54
Cleaning tool
1
338/55
Cleaning patches
1 box
338/132
Filling funnel
1
730/79
Piston support sleeve 71mm
1
338/293
Piston support sleeve 81mm
1
338/294
Die tweezer’s
1
92/0404
RS232 lead MFI10 to PC
1
09/0695
Standard thermometer 188-192°C
1
338/104/3
Thermometer sleeve
1
730/62
Circular spirit level
1
338/100
Spanner 16-17mm
1
91/0095
Hex driver 3/32
1
338/50
Adjustable foot assembly
5
02/0443
Cordset 1
(depending on order)
If there is any damage, or parts missing, please report this to your authorized Davenport
representative.
A
Carefully clean all the parts, removing any preservative that may have been applied to protect
28
MFI 10 User Manual
them during transit and storage. It is strongly recommended that at this stage the small loose parts
should be stored in the wooden tool tray in the base of the MFI in their appropriate recesses The
long tools and piston placed into the pockets located on the top of the unit.
B Choose a suitable site, preferably out of reach of strong draughts, where the apparatus may be
set up more or less permanently.
Place the circular spirit level on top of the barrel, raise the two rear corner feet clear of the work
surface and level the apparatus as exactly as possible by means of the centre rear foot and two front
feet. Once levelled, lower the two rear corner feet to provide stability and lock all feet into place. Do
not move the apparatus. If it has to be moved, ensure that the levelling procedure is repeated in the
new site.
OTE: IT IS IMPORTANT FOR CORRECT FUNCTION THAT THE APPARATUS SHOULD
N
BE LEVEL.
NOTE: It is advisable to check the levelling of the apparatus from time to time, whether it
has been moved or not. It is quite in order for this to be done whilst the machine is hot but in
this case, take care not to leave the circular spirit level on the hot barrel for any
considerable length of time, Despite the insulated base of the level, enough heat will be
generated to burst it over a long period of time.
C Loosen the die plate retaining screws and remove the die plate. Clean the cylinder bore
thoroughly using the cleaning tool and as many cleaning patches as may be necessary, finish off with
a polish using a dry patch.
D Similarly clean the die, paying special attention to the bore which should be polished with a
small wooden stick, (a pared down match stick). Drop the cleaned die into the bore. It must fall
freely and strike the die plate with a clearly audible click. If this does not happen it indicates that either the die or the bore of the barrel (or both) are not perfectly clean and they should be re-examined
and cleaned if necessary.
E The apparatus is supplied with a plug socket and mains lead. Fuses for the apparatus are
incorporated into the inlet socket. Power consumption of the apparatus will not exceed 1KW. An
auxiliary power outlet is fitted with a IEC socket. A maximum of 1 amp is available at this socket.
We are able to supply suitable connecting leads for this socket to enable other peripherals to be
powered directly from the apparatus.
F The temperature controller will start to control the barrel temperature as soon as an electrical
supply is connected, unless the test set-up has been customized to disable this feature.
This controller is calibrated at the factory to give a controlled temperature between 190 and 230° C to
within +0.2° C. If it is necessary to perform tests at higher temperatures, for example 320 - 400°C it
is advisable to set the controller to the desired set point and check the barrel temperature. If an
appreciable difference is apparent, one of two procedures can be followed.
1. An offset can be used by setting the set point of the controller to allow for the difference.
2.
The controller can be re-calibrated against a known accurate thermometer to give the correct
reading at the required set point.
The controller will control to + 0.1 °C of any set point.
3.2 TEMPERATURE CONTROL
MFI 10 User Manual
29
With the apparatus connected to the mains, the temperature controller will start to heat the barrel
to set point (factory set to 190°C). The LED below the temperature displays will indicate that a
controlled output is being applied to the heaters. The set point on the controller can be changed
by means of the keys on the front of the unit. See the section THE MFI 10, Test Procedure of this
manual.
The temperature shown on the digital display may be checked, if required, with a mercury in glass
thermometer following the procedure below.
A Insert the thermometer sleeve into the barrel and ensure that it is fully down against the die
plate.
B Insert a thermometer of suitable range into the thermometer sleeve. Any difference can be
re-adjusted by re-calibration. See the section THE MFI 10, Calibration Mode of this manual.
C If ISO R-1133 standard is being followed, the temperature should be checked with the
thermometer placed directly into the melt of polymer in the barrel.
D Calibration adjustments should be performed 4 minutes after the polymer and thermometer are
loaded into the barrel and all readings are stable.
3.3 CUT-OFF TIMER OPERATION
Although various standard methods are in general agreement, particularly regarding apparatus
specifications, they do differ in certain methodological aspects. The test method described below is,
in our opinion, the best way to use the apparatus for the most consistent, reproducible and
meaningful results, and is supported by prompts on the control panel.
A Allow the barrel temperature to reach a set point and stabilise for at least half an hour. Insert
the die into the barrel. Pre-heat the piston. The LCD will prompt loading when the temperature has
re-stabilised. Remove the piston
B Charge the cylinder with the test sample, introducing it in increments and tamping down each
increment with the charging tool to exclude as much air as possible. Complete the charging
operation in less than one minute. Preheat time will begin with the charging process.
C On completion of the charging operation, insert the piston into the barrel and place the piston
support sleeve so that the piston is supported by the sleeve acting on the rim, with the base of the
sleeve square on the barrel. Two sleeves are provided, the longer for the MFRs greater than one and
the shorter for MFRs less than one.
D Place the appropriate weight on the piston and manually force the test material through the die
until the top of the sleeve prevents further travel of the piston into the barrel. DO NOT purge at the
end of the pre-heat period.
E
When the pre-heat time has elapsed, remove the sleeve to start the test.
CAUTION: The sleeve will be hot.
FWatch the progress of the piston down the barrel. As soon as the lower circumferential ring
on the piston enters the barrel, Cut-Off and press the OK button, discard the extrudate and AT THE
SAME TIME START THE TIMER for the beginning of the test. If the option AFRT is being used the
MFI will start taking readings automatically.
30
MFI 10 User Manual
G Cut-off and retain, in order, specimens of the extrudate at a succession of identical time
intervals.
The time interval used should be chosen on the basis of the expected MFR of the sample (see table),
but whenever possible cut at least 5 samples making quite certain that they are ALL taken when the
lower piston ring is INSIDE the barrel and the upper ring is still outside it.
H
MELT FLOW RATE
GRAMS/600 SECS
0.1 - 0.5
0.5 - 1.0
1.0 - 3.5
3.5 - 10
10 - 25
SAMPLE MASS
GRAMS
4 - 5
4 - 5
4 - 5
6 - 8
6 - 8
CUT-OFF INTERVAL
SECONDS
240
120
60
30
10 - 15
On completion of the test and after all subsequent tests, clean the piston, die and barrel.
See section OPERATING TECHNIQUES, Cleaning.
4.0 CALCULATIONS AND PRESENTATION OF RESULTS
MFI 10 User Manual
31
A Weigh each Cut-Off in the order of the extrusion. Discard any that have obvious air bubbles in
them.
B
Calculate the average weight of the extrudate samples to three significant figures.
C
Calculate the MFR from the equation:
MFR= 10W/T
where:
MFR= Melt Flow Rate in grams per 10 minutes.
W = the average extrudate sample weight.
T = the extrusion time per sample in minutes.
D Report the value thus obtained to two decimal places. When reporting this result always quote
the testing conditions used, such as, the temperature, the load and whether the die used was of
standard geometry or of some other (see notes on operating techniques).
E If the sample was thermally unstable during the test, the successive extrudate samples will have
a continually changing weight. Some materials cross-link, forming high molecular weight groupings
and others degrade due to breaks in the chain. With cross linking the MFR tends to become lower
and the extrudate samples lighter, whilst with chain breaks the MFR will tend to increase so the
samples will become heavier. When a systematic change of mass of this nature is observed, it is
most useful to calculate the extent of the weight change. MELT FLOW RATE SPREAD is not only an
indication of the thermal instability of the sample, but is also used to indicate the significance of the
quoted Melt Flow Rate value.
The MFR Spread is simply the range of extrudate sample weights expressed as a percentage of the
average and calculated from this equation:
Total MFR Spread (%)
=
(Max Weight - Min Weight) X 100
Average Weight
Lower MFR Spread (%) =
(Ave Weight - Min Weight) X 100
Average Weight
Upper MFR Spread (%) =
(Max Weight - Ave Weight) X 100
Average Weight
Using the control panel numeric keypad individual sample weights can be entered into the MFI. The
MFI then calculates and displays the MFR using the equations given above. The MFR and total MFR
spread can be sent to the RS232 interface for printing on the optional ticket printer.
32
MFI 10 User Manual
5.0 OPERATING TECHNIQUES
5.1 CUTTING OFF THE EXTRUDATE
For accurate and repeatable results, the cutting off action should be done quickly and neatly. The tip
of the Cut-Off knife should pass upwards along front side of the conical hole in the die plate, lightly
against the bottom of the die, cutting the extrudate in its passage and continuing down the other side
of the conical hole. The neatness of the cut may be gauged from watching the way the next portion
is extruded. If the cut has been clean and sharp, the emergent strand will point straight down. If not,
there will be a tendency for it to curl, or even stick to one side of the plate hole and emerge in the
form of a loop.
Until some practice in cutting off has been gained, it is helpful to smear a little silicone oil around the
inside of the conical hole. This will help to prevent miss-cuts from sticking to the inside of the hole. It
is also important to avoid allowing the tip of the Cut-Off knife to become hot by holding it in contact
with the side of the die plate orifice between cuts, as this will increase the tendency of the extrudate
to stick to the Cut-Off knife. Keep the tip of the Cut-Off knife sharp and unmarred.
note: DO NOT USE IT AS A SCREWDRIVER.
5.2 THE IMPORTANCE OF PISTON GROOVES
The wall pressure in the barrel INCREASES as the distance between the piston head and the die
DECREASES. Unless this distance is standardised for the purpose of measuring the extrudate flow
rate, very variable results can be obtained from the same sample. This is particularly true of those
materials such as polypropylene which are very pressure sensitive with respect to shear rate. The
purpose of the piston grooving, therefore, is to ensure that all samples are taken over substantially
the same range of pressures in each case, thereby achieving a significant improvement in the
repeatability of the results.
A secondary benefit derived (sometimes erroneously described as the main purpose of the grooving)
is that taking samples over a prescribed and limited part of the piston travel also ensures that they
are all taken over the same temperature gradients, which will no doubt be advantageous in the case
of those melt indexers where there is a pronounced temperature gradient along the barrel length.
5.3 FORM OF TEST SAMPLE
The sample under test may be in any form which can be loaded into the barrel. However, it should
be noted that certain forms, such as films, powder, fibre or any very small particles, are to be avoided
if possible. This is because it is most difficult to exclude air during the charging of such samples.
Included air will produce extrudate containing bubbles and may also promote oxidative degradation of
the sample.
5.4CLEANING
Immediately after each test, the apparatus must be cleaned. Not only is it easier to clean a machine
whilst still hot, but there is less likelihood of the cleaning being forgotten. There is also a real risk of
damage in trying to clean hardened polymer from the operating surfaces. It has been found, as a
result of experience in the field, that the bulk of cases where there has been apparent malfunction of
the apparatus (leading to anomalous results and un-reliability) are due to faulty cleaning, usually over
some time, rather than to component failure. In particular, half-hearted cleaning of the barrel and/
or the die can easily lead to deposits of pyrolysed polymer, often remarkably difficult to see and recognise, effectively reducing the cross-sectional area and markedly affecting the results. The routine
below should be rigorously followed.
MFI 10 User Manual
33
A Remove the piston and clean off any polymer adhering to the head, face and particularly the
shank, with a cloth. Place the cleaned piston in the housing provided on the apparatus.
B Push the die UP the cylinder bore with the die ejector and out of the top. The die ejector will
pass through the hole in the die plate and it is not necessary to remove this. The passage of the die
through the barrel will remove the bulk of any polymer remaining after the test.
C Clean the die thoroughly with a cloth and clean the bore with a diebroach, polishing with a
wooden peg. DO NOT HEAT THE DIE IN A FLAME TO BURN OFF POLYMER.
D Clean the bore of the barrel with the end of the cleaning tool wrapped in a cleaning patch which
has first been folded in half. Push the cleaning tool firmly, with a slight rotating motion, down the barrel but DO NOT FORCE so fast that the tool crashes into the die plate below. Slow down towards the
bottom of the barrel to prevent damaging the die plate, ceramic insert screws and screw holes. Use
as many pieces as necessary to ensure the barrel is thoroughly clean and shiny. A dirty barrel will
cause friction between the piston and the barrel wall and give false low results.
E After each series of tests, or batch exchange, give the machine more thorough cleaning
removing the die plate and cleaning both sides of it and the bottom of the cylinder, in addition to the
routine cleaning process already detailed.
F About every 100 hours use, or once a week for frequent users, remove the die retaining plate
and retaining screws and clean thoroughly. Check the ceramic insert for chips and damage. If the
insert is damaged or covered in blackened polymer, replace it.
G a) The cylinder is hardened, so the bore may be occasionally cleaned with a patch loaded with
a mild metal polish. ON NO ACCOUNT however, use any coarser abrasive material than this.
b) The corrosion resistant barrel is lined with Tungsten Carbide to avoid excessive wear by caustic
(e.g. PVC) or abrasive (glass filled) polymers.
H The dies are made of tungsten carbide, and with reasonably careful use, will maintain their
accuracy over years of service. Dies with PE will last for years, but should be checked regularly. If
PVC or glass filled polymers are used, then the die dimensions should be checked far more often. It
should be cleaned, as already described, by means of the die broach and a wooden peg. Suitable
plug GO/NO GO gauges are available for checking that the bore diameter is within the correct
tolerance. If such a plug gauge is used to check dies in this way, great care must be taken to see that
the die is both perfectly clean and COLD. If there is any dirt in the bore there is a possibility that the
plug gauge will jam and, if this happens, the die will, in all probability, become damaged or chipped
whilst trying to remove it. Similarly, a plug gauge inserted into a hot die will very probably lock due
to differential thermal expansion. In this case make no attempt to force it but allow the whole to cool
down, then the gauge will become free.
IIT IS ABSOLUTELY ESSENTIAL that no die should be used which has any visible imperfection in the bore, particularly any chip, however small, on the edge of the bore opening.
The die ejector is tipped with a soft alloy to prevent damage to the dies.
NOTE: Never use any die ejector which has lost its tip.
34
MFI 10 User Manual
5.5 DIFFERENCES IN TEST CONDITIONS
The standard die is not always considered suitable for use with materials with MFR greater than 25
grams/10 mins. In such cases, a die with a smaller diameter bore, 1.181mm, may be used, (the Jet
B of BS2782). It must never be forgotten, however, that it is impossible to make a strict comparison
between a result obtained with a different sample and the smaller die. Similar caution must be
exercised when considering test temperatures and test loads.
MFI 10 User Manual
35
6.0 AUTOMATIC FLOW RATE TIMER OPERATION
6.1 NOTES OF AUTO FLOW OPERATION
The Auto Flow Rate Timer is calibrated to time the swept volume of a weighted piston travelling
through a pre-selected distance, usually 2mm or 25mm.
The Swept Volume of 2mm = 0.142cc
The Swept Volume of 25mm = 1.776cc
The Auto Flow Rate Time recorded on the display is the time taken to extrude either of the above
volumes and depends on the Standard being applied. In order to obtain the Melt Flow Rate from this
volumetric flow it is necessary to obtain the melt density at the test temperature and load from the
material supplier or by integration of Cut-Off time with the use of the Auto Flow Rate Timer.
6.2 MELT DENSITY CALCULATION
p = m/(0.711 x i)
where:
p = the density (g/cm3) of the melt at the TEST TEMPERATURE.
m = the average mass (g) of the cut-off.
i
= the predetermined distance move by the piston
NOTE: The melt density is NOT the same as the (solid) density at 23°C usually quoted on
the certificate of conformity supplied with the resin. OTE: The GD6250 “Hostalen” resin with an MFI of 1.0 to 1.1g/10mins is used to test all
N
machines before leaving our factory has a density of 0.947 at 23°C but a melt density
of 0.760 at 190°C.
7.0 GENERAL MAINTENANCE
Apart from regular, careful cleaning of the working parts as already described, the Melt Flow Rate
Apparatus requires little maintenance.
In the rare event of component failure, this should be corrected by replacing the defective unit, e.g.
thermometer. If the apparatus is to be taken out of use for any length of time, it should be given a
very thorough clean, after which all exposed metal parts should be protected with a light greasing
before storing the apparatus in a DRY PLACE and under dust covers.
Under these conditions the Melt Flow Indexer should give many years of trouble free service.
36
MFI 10 User Manual
8.0THERMOMETERS
We take care to pack our thermometers so that they will not be damaged in transit. Even though it
may still be that, due to vibration, breaks have appeared in the mercury column. These can easily be
repaired and MUST be looked for before using the thermometer as, if one exists and is not noticed, a
false temperature indication will be given as well as the possibility of the mercury bulb breaking.
8.1 REPAIRING BREAKS IN MERCURY COLUMN TYPES OF THERMOMETERS
A break in the mercury column can usually be detected by eye. If it is not it will be seen as soon as it
is put into a heated barrel. The mercury will shoot up beyond the maximum temperature very quickly,
where as under normal operation the movement of the mercury column will be quite slow. If the
mercury does shoot up very quickly, immediately remove it from the barrel and allow to cool down.
Then shake the thermometer firmly and decisively, with downward strokes to force the mercury back
down into the bulb. Repeat if necessary. If this does not work place in the freezer compartment of a
normal domestic refrigerator for about two minutes to retract the mercury into the bulb.
RS Components also supply a cryogenic spray which is much more convenient. DO NOT USE
LIQUID NITROGEN, IT IS TOO COLD. DO NOT leave the thermometer in a cold place as this may
solidify the mercury. Then the thermometer should be returned to room temperature slowly as rapid
warming may burst the bulb owing to the pressure generated in forcing the Mercury through the
capillary. Whether to heat or cool depends on the position of the break. Those near the bulb are best
rejoined by cooling and visa versa.
8.2 THERMOMETERS WITH CONTRACTION AND EXPANSION CHAMBERS
If the detached part of the column is above the contraction chamber, rejoin the expansion chamber
by heating as already explained. If there are breaks in the mercury in the contraction chamber, firmly
but smoothly swing the thermometer bulb downwards, as when shaking down a clinical thermometer.
If this fails, tap the bulb vertically on the palm of the hand. Occasionally a small globule of mercury is
left in the neck of the contraction chamber. It can often most easily be reunited by heating the
thermometer to drive it some way up the stem and then chilling the bulb. The detached piece will
shoot back down the capillary and fly into the contraction chamber.
8.3 RED SPIRIT THERMOMETERS
It is not unusual for these to exhibit breaks. If they occur they can be rejoined by freezing the bulb.
NOTE: DO NOT ATTEMPT TO REJOIN BY HEATING
MFI 10 User Manual
37
8.4 GENERAL CARE OF THERMOMETERS IN USE
Thermometers must be treated with care. Being made of glass, they are not only mechanically
fragile, but also cannot withstand excessive thermal shocks, either by heating or by cooling. It is
therefore always better to allow a thermometer to warm up and cool down gradually. If it is necessary
to change thermometers during use DO NOT put hot thermometers onto cold conductive surfaces.
Try to warm up cold thermometers gradually, rather than plunging them directly into high temperature
environments.
38
MFI 10 User Manual
9.0SPECIFICATIONS
MFI Specification
Temperature Range
40°C to 400°C with 20 minutes warm up time from ambient to 190°C
Temperature Controller
All systems + 0.1°C accuracy
Mounting
All systems are bench mounted
Electrical Supply
MFI 10 & MFI 10/CB, 230V ac +10% 50 - 60Hz, Fuses 5A(T)
MFI 10/110 & MFI 10/110/CB, 115V ac +10% 50 - 60Hz,Fuses 10A (T)
Maximum power requirement 1 kW. via I.E.C. plug. (CN 1)
Overall Dimensions
Height 600mm, Width 463mm, Depth 404mm
Weight, with standard accessories Unpacked 32kg (71 lbs)
Packed (in wooden crate) 53kg (117 lbs)
Operating Conditions
5°C to 45°C (41°F to 129°F)
0 - 80% RH non condensing. Well ventilated, draught free.
Storage Conditions
-20°C to 55°C, Substantially Dry (-4°F to 131°F)
i/p & o/p Connections
CN1 - I.E.C. Plug, Mains In.
CN2 - I.E.C. Socket, Mains Out, 250VA max.
CN3 - 9 Pin “D” Plug, RS232 interface.
CN4 - 15 Way “D” Socket, Auto Cut Off & Analogue O/P
CN5 - 15 Way “D” Socket, Weight Loading System &
Analogue. O/P.
CN6 - 9 Way “D” Socket, Automatic Flow Rate Timer.
Standards
ISO1133 BS2782: Part 7: Method 720A , ASTM D1238 (Procedures A & B)
- Procedure B requires optional Automatic Flow Rate Timer
NFT
UNE
UNI
DIN
MFI 10 User Manual
39
10.0 CONNECTION LEADS
10.1 RS232 LEADS
MFI10 to PC Lloyd Part No. 09/0695 ( supplied )
9 Way “D”
SKT (Female)
9 Way “D”
SKT (Female)
RxD 2
2 RxD
TxD 3
3 TxD
DCD 1
1 DCD
DTR 4
4 DTR
RTS 7
7 RTS
CTS 8
8 CTS
GND 5
5 GND
Baud rate 4800, 8 bit, 1 Stop bit, No parity
MFI10 to Citizen Printer Lloyd Part No. 09/0644 ( optional )
25 Way “D”
SKT (Male)
Printer End
9 Way “D”
SKT (Female)
MFI10 End
TxD 3
3 RxD
CTS 8
20 DTR
GND 5
7 GND
Baud Rate 4800, 8 bit, 1 Stop bit, No parity.
Note: To maintain EMC compliance ONLY leads supplied by Lloyd Instruments should be used.
Check leads for signs of damage regularly. Replace leads that are damaged in any way.
40
MFI 10 User Manual
International Symbols
WEEE Directive
This equipment contains electrical and electronic circuits
and should not be directly disposed of in a landfill site.
RoHS
This product is RoHS and China RoHS compliant. This
symbol indicates the equipment contains some restricted
hazardous substances above the recommended level, and
may offer potential harm to the environment after 15 years
from date of manufacture.
www.lloyd-instruments.com
UK
Denmark
Singapore
France
USA
China
Germany
India
Lloyd Instruments Ltd
Tel +44 (0)1243 833 370
uk-far.general@ametek.co.uk
AMETEK S.A.S.
Tel +33 (0)1 30 68 89 40
general.lloyd-instruments@ametek.fr
AMETEK GmbH
Tel +49 (0)2159 9136 510
info.mct-de@ametek.de
AMETEK Denmark
Tel +45 4816 8000
ametek@ametek.dk
AMETEK Measurement & Calibration Technologies
Tel +1 (727) 536 7831
chatillon.fl-lar@ametek.com
AMETEK Instruments India Pvt Ltd.
Tel +91 22 2836 4750
ametek@ametek.dk
AMETEK Singapore Pte Ltd
Tel +65 6484 2388
aspl@ametek.com.sg
AMETEK Inc. - Shanghai
Tel +86 21 5868 5111
AMETEK Inc. - Beijing
Tel +86 10 8526 2111
AMETEK Inc. - Guangzhou
Tel +86 20 8363 4768
lloyd@ametek.com.cn
MFI 10 User Manual
Information in this document is subject to change without notice. ©2012 by AMETEK, Inc., www.ametek.com. All rights reserved.
41
Download PDF